In order to determine proper installation and operation of an object, it is often necessary to confirm that the rotation angle of the object falls within or meets certain specifications. For example, the steering geometry and, particularly, the rotation angle of the wheels as they are rotated by the steering linkage is an important consideration to the proper operation of a motor vehicle. Accordingly, it is necessary to accurately assess the rotation angle of the wheels when cut to the left or right.
While many devices have been built in the past for this purpose, none are able to effectively compensate for the "floating axis" about which each wheel rotates. More specifically, because of the caster of the wheel, the rotation axis shifts when the wheel is turned by operation of the steering wheel. This shift in the rotation axis, if not effectively compensated for, will adversely effect the accuracy of any measurement of true rotation angle.